GB2286015A

GB2286015A - Air intake unit of an i.c.engine

Info

Publication number: GB2286015A
Application number: GB9501653A
Authority: GB
Inventors: Erwin Rutschmann; Wolfgang Horlacher
Original assignee: Dr Ing HCF Porsche AG
Current assignee: Dr Ing HCF Porsche AG
Priority date: 1994-01-29
Filing date: 1995-01-27
Publication date: 1995-08-02
Anticipated expiration: 2015-01-27
Also published as: GB2286015B; GB9501653D0; US5495834A; JPH07224670A

Abstract

The unit of an engine with two banks of cylinders comprises a chamber 5, 6 and intake pipes 9 for each cylinder bank and a further chamber 14 centrally therebetween. The chambers 5, 6 are connected by connecting pipes 11 and air enters the chambers 5, 6, 14 through inlets 13, 18. Intake pipe extensions 15 are connected to the further chamber 14 and extend into the chambers 5, 6 and are spaced from but in alignment with inflow funnels 10 of the intake pipes 9. Sleeves 30 mounted on the extensions 15 may be movable to abut the funnels 10 above about 5000rpm. The sleeves 30 in each chamber 5, 6 may be formed as a light metal or plastics unit with the units in the two chambers operated by a common actuator (32, Figs. 5 and 6). The extensions 15 within the chambers 5, 6 may be formed by sheet steel tubes (36, Fig. 5) located with play in the chamber walls. <IMAGE>

Description

i 1 Air-Intake Unit of a Multiple-Cylinder Internal-Combustion Engine

2286015 This invention relates to an air-intake unit of a multiple-cylinder internal-combustion engine with two opposed rows of cylinders, wherein the cylinders of each row are connected by intake pipes to a respective resonance chamber, the resonance chambers being interconnected by means of a connecting pipe and having intake-pipe extensions extending in part inside the resonance chambers and comprising sleeves slidable between inlet openings of the intake pipes from a first spaced position into a second non-spaced position as a function of operating parameters of the internal-combustion engine.

The air-intake unit of German Application P 43 15 129.9-13 provides an example of increasing the average pressure over the entire rotational speed range. In this way, an increased,quantity of fresh air is supplied to each cylinder, and this results in a perceptible improvement in the delivery rate.

An object of the invention is to optimize this air-intake unit in terms of its structure and 2 manufacture while having a satisfactory operation.

The invention provides an air-intake unit as claimed in Claim 1. Further preferred features of the invention are as claimed in the Sub-Claims.

The advantages mainly achieved by the invention are that the sliding sleeves are associated with an easily producible structural unit, the sliding sleeves surrounding the inserts constructed in a simple manner and integrated in the air-intake unit so as to provide proper functioning.

The preferred tolerance-compensating mounting of the inserts ensures satisfactory operation of the sliding sleeves. The preferred fastening of the respective insert to the housing of the air-intake unit with a collar and a circlip is inexpensive and reliable in operation.

Operational reliability may be further assisted by the special matching of the materials, namely the housing and the sliding sleeves of an aluminium alloy and the inserts of a ferrous-metal material, for example thin metal sheet.

Preferably, the control device engages in a line of 1 3 the centre of gravity of the structural unit, as a result of which favourable conditions of actuation can be achieved.

Finally, the slit opening of the lever and the cylindrical pin of the preferred structural unit constitute a transmission member which is simple to produce but highly effective.

Embodiments of the invention will now be described with reference to the accompanying drawings, wherein:

Fig. 1 is a side view of a first embodiment of an air-intake unit with a modification in the left-hand half of the Figure, Fig. 2 is a plan view in the direction of the arrow X of Fig. 1, Fig. 3 is a view similar to Fig. 1 of a second embodiment, Fig. 4 is a plan view in the direction of the arrow Y of Fig. 3, Fig. 5 is a view in the direction of the arrow Z of Fig. 3 on an enlarged scale, and 4 Fig. 6 is a section along the line VI-VI of Fig. 5.

An internal-combustion engine with two cylinder rows 1, 2 has an airintake unit comprising a two-chamber resonance system 3 and a singlechamber oscillation-tube system 4. The resonance system 3 comprises resonance chambers 5, 6, which are associated with the cylinder rows 1, 2 and to which individual intake pipes 9 leading to the cylinders 7, 8 of the internal-combustion engine are connected by means of inlet funnels.

In addition, the resonance system 3 comprises two connecting pipes 11, 12 connected to the resonance chambers 5, 6, air being supplied to one connecting pipe 11 by way of a fresh-air inlet 13.

A chamber 14, extending along its greatest length in a longitudinal direction R of the cylinder rows 1, 2, is arranged in a plane of symmetry EE substantially centrally between the resonance chambers 5, 6. Intakepipe extensions 15 are connected to the chamber 14 on both sides thereof, and are provided with cylindrical intake-pipe extension portions 16 which extend inside the resonance chambers 5, 6. The intake-pipe extensions 15 form the single-chamber. oscillation-tube system 4 jointly with the chamber 14. The portions 16 are spaced from, and are arranged v t coaxially in alignment with, the inlet funnels 10. The distance H (see Fig. 1) produced defines an annular gap 17.

In Fig. 1, of which only the part situated to the right of the plane E-E is initially relevant, shows a first embodiment. The chamber 14 has a fresh-air inlet 18. Air is drawn into the system through the fresh-air inlet 18 and the further fresh-air inlet 13. Air flows both through the connecting pipes 11, 12 acting as resonance tubes and through the intakepipe extensions 15 acting as oscillation tubes via the annular gap 17 to arrive at the cylinders 7, 8.

The middle one of the intake-pipe extensions 15 has a controllable throttle valve 19. This intake-pipe extension 15 acts as an additional resonance tube at certain rotational speeds and thus contributes to an increase in torque.

In order that the further connecting tube 12 may be switched on as desired, it has a controllable throttle valve 20.

In a second embodiment according to Fig. 3, the first and the further fresh-air inlet 13 and 18 are arranged jointly in an inlet opening 21 in the chamber 6 14, which extends in the manner of a disc in the plane E-E. The connecting pipes 11, 12 are divided, each pipe part 22, 23, 24, 25 extending between one resonance chamber 5, 6 and the chamber 14 and each having a controllable throttle valve.

On the left hand side of Pigs. 1 and 3, a modification of the respective embodiments is shown having a sliding sleeve 30 displaceably mounted on the portion 16. A displacement mechanism is shown in Fig. 3. The sliding sleeves 30 arranged in a respective resonance chamber 5, 6 are combined to form a structural unit 31, which is displaceable by means of a control member constructed in the form of a pneumatic pressure box 32 and a rod 33 so as to bridge the annular gap 17 in a manner known per se and therefore not described in greater detail.

In a first rotational speed range of up to about 5000 rpm a high torque is achieved by long intake pipes and a relatively small overall volume of the air-intake system. To this end, in this operating range of the internal-combustion engine, the pressure box 32 moves the structural unit 31 into a position which closes the annular gap 17, as indicated in broken lines in Fig. 3. When the resonance chambers 5, 6 are disconnected, freshly drawn-in air now arrives in the intake pipes 9 R 1 7 by way of the fresh-air inlet 18 and the connected intake-pipe extension 15 only. After reaching a second rotational speed range, of between 5000 and 7000 rpm, the pressure box 32 moves the structural unit 31 into a position of the sliding sleeve 30 as indicated in continuous lines in Pigs. 1 and 3. Freshly drawn-in air now arrives at the annular gap 17 with the interposition of the resonance chambers 5, 6 as well as by way of connecting pipes 11, 12 connectable stepwise and by way of the portions 16.

The structural unit 31 formed by the sliding sleeves 30 is produced in one piece in accordance with Fig. 5, the cylindrical sliding sleeves 30 being connected to one another by webs 34. In the embodiment shown the structural unit 31 consists of a light metal alloy. it is also possible, however, to produce it from plastics material. This choice of material is also possible for an air-inlet unit 35 which surrounds the structural unit 31.

The intake-pipe extension portions 16 are constructed in the form of separate inserts 36 which are inserted in a housing 37 (for example of a light metal alloy, plastics material or the like) of the air-intake unit 35, namely in such a way that they compensate tolerances in the radial direction Rr. This ensures 8 that the structural unit can be actuated without interference between the positions A and B. To this end, each insert 36, which may be produced from thin-walled steel sheet, extends with a collar 38 to an intake-pipe portion 39 of the housing 37. There the collar 38 is held in position by means of a positively locking circlip 40. In the region of the collar 38 the intake-pipe portion 39 has a thickening 41, which on the one hand receives the circlip 40, and on the other hand acts as a stop 42 for the sliding sleeve 30 (position B). On the end facing the intake pipe 9 the sliding sleeve 30 has a sealing member 43 which in position A, i.e. the zero-distance position of the sliding sleeve 30, is connected in a flow- tight manner by a sealing 44 to the inlet funnel 10 of an adjacent intake- pipe connexion 45 of the intake pipe 9.

The control device 46, which is constructed as a pressure box 32 and which could also be a solenoid valve, is secured to the housing 37 and engages in a plane C-C (line of centre of gravity) which extends at an equal parallel distance D from the median lines F-F and G-G of the inserts 36, so as to produce substantially a state of equilibrium of the structural unit 31.

The control device 46 comprises a rotating shaft 47 9 with a lever 48 which surrounds a cylindrical pin 50 of the structural unit 31 with a slit opening 49. The rotating shaft 47 is arranged inside a bearing bush 51 which is secured in a bore 52 in a bearing thickening 53 of the housing 37.

Claims

Claims:

An air-intake unit of a multiple-cylinder internal-combustion engine with two opposed rows of cylinders, wherein the cylinders of each row are connected by intake pipes to a respective resonance chamber, the resonance chambers being interconnected by means of a connecting pipe and having intakepipe extensions extending in part inside the resonance chambers and comprising sleeves slidable between inlet openings of the intake pipes from a first spaced position into a second non-spaced position as a function of operating parameters of the internal-combustion engine, characterized in that a plurality of sliding sleeves of a cylinder row are interconnected to form a structural unit operatively connected to a control device, and the sliding sleeves surround intake- pipe extension portions constructed in the form of inserts.
2. An air-intake unit according to Claim 1, wherein the inserts are held on a housing of the air-intake unit in such a way as to compensate for radial tolerance.
An air-intake unit according to Claims 1 or 2, wherein each insert extends up to an intake-pipe portion of the housing with a collar, and the collar f 11 is held in position by means of a positively locking retaining member.
An air-intake unit as claimed in Claim 3, wherein the positively locking retaining member is a circlip.
5. An air-intake unit according to Claim 3 or 4, wherein adjacent the collar the intake-pipe portion has a thickening receiving the retaining member and acting as a stop for the sliding sleeve.
6. An air-intake unit according to any one of the preceding claims, wherein the housing and the sliding sleeves forming the structural unit consist of an aluminium alloy, whereas the inserts consist of a ferrousmetal material.
7. An air-intake unit according to any one of the preceding claims, wherein, the sliding sleeves are provided with sealing members on the ends thereof facing inlet funnels of intake-pipe connections of the intake pipes.
8. An air-intake unit according to any one of the preceding claims, wherein the control device engages the unit in a plane extending at an equal distance from the median planes of the inserts of respective 12 resonance chambers.
9. An air-intake unit according to Claim 8, wherein the control device comprises a rotating shaft with a lever surrounding with a slit opening a cylindrical pin of the structural unit.
10. An air-intake unit substantially as herein described with reference to any one of the embodiments shown in the accompanying drawings.

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